Method and device for the retraction and hemostasis of tissue during crown and bridge procedures

ABSTRACT

A method and a device for effecting the cordless retraction of the gingival sulcus tissue prior to the taking of an impression of a tooth for making a crown or bridge which is attained by controlling any bleeding in the gingival sulcus area, and utilizing a dental dam preferably formed of a sponge or foam like material to contain an astringent fortified silicone impression material embedded about the prepared tooth, and using the patient&#39;s biting force to apply the necessary pressure onto the dam until the silicone impression material sets and adheres to the dam to enhance easy removal of the set impression material from the tooth. The dam is formed to accommodate either the posterior teeth or the anterior teeth.

FIELD OF THE INVENTION

This invention is directed to a method and device for effectinghemostasis retraction of tissue, and more specifically to a method anddevice for the retraction and hemostasis of tissue in preparing a toothprior to the taking of an impression for forming a crown or bridgedental prosthesis.

BACKGROUND OF THE INVENTION

The traditional method for controlling hemostasis and retraction ofgingival tissue prior to the taking of an impression of a prepared toothto form a crown or bridge is to mechanically pack a small length of cordsaturated with an astringent about the base of the tooth to enlarge thegingival sulcus space about the base of a tooth. After a period of time,the cord is removed from the enlarged space defined about the base ofthe tooth. Upon the removal of the cord, it frequently happens thatcoagulum formed to stop the bleeding or seepage of fluid is removed withthe cord to result in the seepage of additional bleeding into the space.As a result, an impression cannot be made of the prepared tooth untilthe additional bleeding can be controlled or stopped. Thus, thetraditional procedure for enlarging the space between the gum and thebase of the tooth necessary for taking an accurate impression istedious, time consuming and painful or extremely uncomfortable for thepatient. Also, there exists the danger that the dentist may accidentallyforce the cord beyond the physiologic limit of the space to create apotential periodontal pocket which can cause the tooth to be eventuallylost. The general practice of using the cord technique is relativelydifficult and tedious for the dentist. In the event that the spacebetween the tooth and the gum that has to be retracted is very small, itbecomes even more difficult for the dentist to place the cord withoutinjuring the gum tissue and from forcing the cord beyond the physiologiclimit, and renders the procedure more painful for the patient. Further,the placing of the cord is not a procedure which the dentist maydelegate to a dental assistant or dental hygienist. Also, the packing ofa retraction cord is a most disliked step to perform during a crown orbridge restoration procedure.

Efforts have been made to obviate the noted disadvantages of affectingthe retraction of the gingival tissue by the use of a cord. One suchknown effort is the use of a kaolin type material that is mixed with anastringent salt which is simply placed about a prepared tooth to absorbthe moisture to cause the gum tissue to shrink. Such a product ismarketed by Sybron Dental Specialties under the brand name EXPASYL.

It has been noted that such kaolin type material is packaged in acartridge similar to a typical anesthetic cartridge commonly used in adental office that requires the cartridge to be used with a syringe. Theend of the cartridge is pierced with a needlelike cannula and the forceof the syringing pressure is required to extrude the clay like kaolinmaterial through the cannula. Because of the density of the kaolin typematerial, the cannula requires the opening to be very large so as toenable the kaolin type material to flow therethrough. The large guageopening of the cannula renders the bending of the cannula difficult andwhich bending is often required in order to place the material indifficult to reach places within a patient's mouth. Because the openingof the cannula is quite large, difficulty is encountered in placing thekaolin type material about the gingival sulcus in a manner similar tothe traditional method of packing cord to retract the gum tissue. Use ofsuch kaolin type material to retract the gum tissue tends to crumble,rendering it difficult to place in the space between the gum tissue andthe tooth to attain the desired retraction of the gum tissue. Anothernoted problem with such kaolin type material is the removal of thekaolin material after the period of time required to affect thehemostasis and the retraction. Generally, the kaolin material isrequired to be washed out using a water-air spray with extreme care toremove all the kaolin material without restarting any bleeding in thegingival sulcus.

Another known technique for effecting a non-cord retraction andhemostasis is disclosed in my prior U.S. Pat. No. 5,676,543. Thereindisclosed is a generally two part process utilizing two differentviscosities of a condensation silicone material to effect the cordlessretraction and hemostasis of the gingival sulcus.

This invention is directed to an improvement to the non-cord retractionand hemostasis procedure described in my prior U.S. Pat. No. 5,676,543.This invention is directed to a more simplified non-cord retraction andhemostasis process and a device for accomplishing the same.

SUMMARY OF THE INVENTION

An object of this invention is to provide a one part cordless retractionmethod for enlarging the gingival sulcus space between the gum tissueand the prepared tooth prior to the taking of an impression during acrown or bridge procedure.

Another object is to provide a foam, rubber or sponge like dam foreffecting the cordless retraction and hemostasis of the gingival sulcusof a prepared tooth prior to the taking of an impression.

Another object is to provide for a hemostasis and cordless retraction ofthe gingival sulcus using the patient's own biting pressure to force theretraction material into the space between the gum tissue and theprepared tooth to enlarge the same.

Another object is to provide a cordless hemostasis and retraction methodwhich is positive in operation and simple to perform.

Another object is to provide for a cordless hemostasis retraction methodof the gingival sulcus area, which is painless, comfortable and easy onthe patient, and easy for the dentist to perform.

The foregoing objects and other features are attained by the method offirst preparing a tooth to be restored for taking an impression thereofin preparation of forming a crown or bridge. After the tooth has beenproperly prepared and before a proper impression can be made, the gumtissue about the base of the tooth must be retracted so as to enlargethe gingival sulcus. This is achieved in accordance with this inventionby the injection of a suitable liquid astringent about the base of thetooth to control or stop any excessive bleeding or seepage of fluid.This can be attained by the application of a liquid hemostasis agent,e.g. aluminum chloride, ferric sulfate and the like to the cut tissue bysyringing or other suitable applicator. Where bleeding is slight orminimal, it may not be necessary to apply any astringent. After thecontrolled hemostasis, a foam or sponge like dam having a groove ortrough is adjusted and fitted so as to cover at least one tooth mescaland distal beyond the prepared tooth. The foam or sponge dam so formedis then filled with a silicone type impression material which isfortified with a hemostatic agent. A predetermined amount of thefortified silicone impression material is also placed about the entirecircumference of the prepared tooth at the gingival sulcus margin,preferably by syringing. The application of the silicone impressionmaterial is then generously applied to cover the entire prepared tooth.The sponge or foam dam filled with the silicone impression material isthen placed over the silicone covered tooth, at which time the patientis instructed to apply a biting pressure onto the sponge or foam dam andto maintain the biting pressure thereon for a predetermined time periodsufficient for the silicone-impression material to set, e.g. 5 to 7minutes. The sponge or foam dam is then removed together with the set orcured silicone material which remains adhered to the sponge or foam dam.Upon removal of the dam, the tooth may be lightly washed and examined inpreparation of the taking of the impression. If additional retraction ofthe gum tissue is required, the procedure may be repeated.

IN THE DRAWINGS

FIG. 1 is a side view of a prepared tooth and illustrating the placementof a liquid hemostatic agent to control bleeding about the gingivalsulcus area.

FIG. 2 illustrates the filling of the groove of a sponge or foam dam foruse on posterior teeth with an amount of impression material.

FIG. 3 illustrates the intermediate step of placing the siliconeimpression material about the gingival sulcus area.

FIG. 4 illustrates the generous application of the silicone impressionmaterial covering the entire prepared tooth.

FIG. 5 illustrates the step of placing the filled sponge or foam damonto the covering of the prepared tooth and the application of a bitingpressure thereon.

FIG. 6 is a view similar to that of FIG. 5 to illustrate the retractionand enlargement of the space between the retracted gum tissue and thebase of the prepared tooth with the dam and impression material removed.

FIG. 7 illustrates a perspective view of a slightly modified sponge orfoam dam for use in the cordless retraction of the gum tissue aboutanterior teeth.

DETAILED DESCRIPTION

Referring to the drawings, there is shown a tooth 20 which has beenprepared for receiving a crown or bridge. However, before the impressioncan be taken for preparing the crown or bridge, it is imperative thatthe gingival sulcus tissue 21 be retracted in order for the dentist tomake an accurate impression of the prepared tooth 20. In accordance withthis invention and to control any excessive gingival bleeding, anapplication of a liquid hemostatic agent 22, e.g. aluminum chloride,ferric sulfate or other suitable astringent is applied to the cut tissuein the area of the gingival sulcus. The astringent can be applied withCentrix's Benda micro applicator 23 as seen in FIG. 1, or by any othersuitable applicator, e.g. Centrix, Inc.'s BENDA® brush, SoftStix™disposable applicator, or syringe, and the like. The astringent 22 isapplied with moderate pressure and by rubbing the astringent solutionagainst the cut tissue to infuse the astringent solution into the cutcapillaries. After the bleeding is under control, a dam 24 is adjustedand fitted to the prepared tooth 20 and to at least one tooth mescal anddistal beyond the prepared tooth or teeth 20.

In accordance with this invention, the dam 24 is formed of a porous foamor sponge type material which may be either natural or synthetic. Thedam 24, as shown in FIG. 4, is formed for use on posterior teeth.

As shown, the dam 24 may be formed as an elongated block of a sponge,foam, or other type of porous material. It will be understood that theblock of foam or sponge may be of any desired length from which thedentist may sever therefrom the desired length necessary to dam one ormore teeth being worked upon. Conversely, the dam 24 may be pre-cut tosize, depending upon the number of teeth that may require gum retractionand to which the finished crown or bridge is to be applied. As seen inFIG. 4, the foam or sponge dam 24 is provided with a longitudinallyU-shaped groove or trough 24A extending along the length thereof. Therespective opposed side walls 24B and 24C and interconnected web orbottom 24D, as shown in FIG. 4, are sufficiently thick to contain andexert the necessary pressure to effect the gum tissue retraction as willbe herein described.

FIG. 7 illustrates a modified block of sponge or foam material fromwhich a modified dam construction for use with anterior teeth is formed,as will be hereinafter described.

After the bleeding of the gum tissue to be retracted is controlled, thegroove 24A of an appropriate size dam 24 is filled with a hereinbeforedescribed fortified silicone type impression material 26, as shown inFIG. 2. The silicone material 26 may comprise a two-part compositionwhich includes a base portion and a catalyst portion which, when mixed,will quickly set and become solid. The time of setting can be variedwithin a predetermined time range by controlling the ratio of catalystto base. Such silicones are available from various manufacturers, e.g.CONQUEST by Pentron, EXAFLEX by G.C., EXTRUDE by Kerr Corporation orIMPRESS and EXPRESS by 3M Corporation. While the silicone materials arepreferred, other materials such as polyethers, polysulfides and anyother dental moldable materials may be used. The condensation siliconematerials are preferred. The silicone material 26 is further fortifiedwith between five percent (5%) to twenty percent (20%) by weight of asuitable astringent to aid in the gum tissue retraction and hemostasis.Any of the known astringents may be used which are rendered compatiblewith the silicone. Some of the known astringents or hemostasis agentsare aluminum potassium sulfate, aluminum sulfate, or alum, ferricsulfate, aluminum ammonionium sulfate, ferric chloride, aluminumchloride, sodium chloride, zinc chloride and others.

The same silicone material is also applied about the gingival sulcusarea as shown in FIG. 3, preferably by syringing. The entire preparedtooth 20 is then covered with the same silicone material as shown inFIG. 4. It will be understood that the step of applying the siliconematerial to the dam 24 or about the tooth as shown in FIGS. 3 and 4 canbe reversed. With the tooth covered with the silicone material 26, andwith the groove 24A of the dam 24 filled with the same siliconematerial, the silicone-filled dam 24 is placed onto the silicone coveredtooth, as best seen in FIG. 5.

With the filled dam 24 disposed over the silicone covered tooth orteeth, the patient is instructed to apply a biting force or pressureonto the dam 22 as shown in FIG. 5, and to maintain the biting pressureon the dam 24 until such time that the silicone material sets,approximately 5 to 7 minutes. Upon setting of the silicone material, thedam 24 and the set moldable material is removed to expose the preparedtooth as shown in FIG. 6. As the dam 24 is formed of a porous or foamsponge-like material, the silicone material, upon setting, willpenetrate the pores of the foam material, causing the set siliconematerial to mechanically adhere to the dam 24 whereby the set siliconematerial can be removed in unison upon the removal of the dam 24. Thetooth may then be lightly washed, dried and examined to determine if thegum tissue has been sufficiently retracted so as to enable an accurateimpression to be made.

The bite pressure imparted by the patient onto the dam 24 as seen inFIG. 5, causes the silicone impression material to be forced into thegingival sulcus space, which together with the interaction of theastringent material causes the gum tissue in the gingival sulcus area toretract to enlarge the space 27 between the tooth and surrounding gumtissue as noted in FIG. 6. In the event additional retraction of the gumtissue is required, the procedure hereinabove described may be repeated.

While the sponge or foam dams 24, as described herein, are preferred, itwill be understood that other means may be used in lieu of the foam orsponge dams, e.g. a cotton roll or hollowed cotton gauze or pad, orother suitable material capable of containing the silicone, astringentbased, material when the biting pressure is applied and maintained. Theuse of the biting pressure on the dam 24 causes the silicone materialcontaining the astringent material to be forced onto the gingival sulcusspace, causing the gum tissue to be retracted an amount sufficient topermit an accurate tooth impression to be made for making a crown orbridge.

While the method described is in reference to retracting the gum tissueof a posterior tooth, the same method is applicable for retracting thegum tissue of an anterior tooth. However, for an anterior gumretraction, the dam is preferably constructed with a V-shaped groove, asin FIG. 7.

Referring to FIG. 7, an anterior dam 28 may be severed from an elongatedblock 29 of foam or sponge like material similar to that hereinbeforedescribed, except the groove 30 is generally V-shaped as shown in FIG.7. The opposed sides of the V-shaped groove 30 converge inwardly of thefoam or sponge block. In all other respects, the construction of dam 28and the use thereof is similar to that described with respect to theconstruction and use of dam 24. It will be understood that the foammaterial, from which the described dams are made, may be formed of openor closed cells, natural or synthetic foam or sponge.

The method described and the dam for effecting the same is relativelysimple, expedient and results in a positive retraction of the gum tissueso as to ensure that all margins can be captured in a subsequentimpression procedure. The described invention further reduces the traumaand discomfort often encountered by the patient in a gum retractionprocedure. Also, the present invention provides enhanced results withmuch greater ease on the part of the dentist. The procedure is renderedso simple that it can be delegated to a dental assistant.

While the preferred embodiments of the present invention have beenillustrated and described, it will be obvious to those skilled in theart that various modifications may be made without departing from thespirit and scope of this invention.

1. A non-cord method of retracting gum tissue in preparation for takingan impression comprising: (a) preparing a tooth for restoration; (b)controlling any bleeding occurring with respect to any cut tissue in thegingival sulcus area; (c) placing an amount of an impression materialinto the groove of a dental dam made of a porous material; (d) coveringthe prepared tooth with a layer of said impression material; (e) placingthe trough of the dental dam filled with the impression material ontothe prepared tooth covered with the impression material; (f) requiringthe patient to apply a biting pressure onto the dental dam; (g)permitting the impression material to penetrate the porous material ofthe dental dam; (h) maintaining the biting pressure on the dental damuntil the impression material has set; and (i) removing the dental damwith the impression material attached from within the patient's mouth.2. A non-cord method of retracting gum tissue as defined in claim 1wherein steps (c) and (d) may be reversed.
 3. A non-cord method ofretracting gum tissue as defined in claim 1 wherein the dental dam isformed of a porous foam material.
 4. A non-cord method of retracting gumtissue as defined in claim 3 wherein: said dental dam is formed as anelongated block of said foam material having a groove extendinglongitudinally of said block, and said block being of sufficientthickness to retain the impression material confined within said groovewhen a biting pressure is applied thereto.
 5. A non-cord method ofretracting gum tissue as defined in claim 1 wherein said impressionmaterial used comprises a two-part composition which includes a baseportion and a catalyst portion which, when mixed, will quickly set.
 6. Anon-cord method of retracting gum tissue as defined in claim 5 whereinsaid composition used is fortified with an astringent selected from thegroup consisting of aluminum potassium sulfate, potassium aluminumsulfate, aluminum sulfate, alum, ferric sulfate, aluminum ammonioniumsulfate, ferric chloride, aluminum chloride, sodium chloride and zincchloride.
 7. A non-cord method of retracting gum tissue for taking atooth impression comprising: (a) controlling any bleeding occurring withrespect to any cut tissue in the gingival sulcus area; (b) covering theprepared tooth with a generous amount of impression material; (c)placing the groove of a dental dam made of a porous material onto theprepared tooth covered with the impression material; (d) requiring thepatient to apply a biting pressure onto the dental dam; (e) permittingthe impression material to penetrate the porous material of the dentaldam; (f) maintaining the biting pressure on the dental dam until theimpression material has set; (g) removing the dental dam with theimpression material attached from within the patient's mouth.
 8. Anon-cord method of retracting gum tissue as defined in claim 7 whereinsaid dental dam is formed of a cellular foam material.
 9. A non-cordmethod of retracting gum tissue in preparation for taking a toothimpression comprising: (a) placing an amount of an impression materialinto the groove of a dental dam made of a porous material; (b) coveringthe prepared tooth with a layer of said impression material; (c) placingthe trough of the dental dam filled with the impression material ontothe prepared tooth covered with said impression material; (d) requiringthe patient to apply a biting pressure onto dental dam; (e) permittingthe impression material to penetrate the porous material of the dentaldam; (f) maintaining the biting pressure on the dental dam until theimpression material has set; (g) removing the dental dam with theimpression material attached from within the patient's mouth.
 10. Adevice for effecting the cordless retraction of gum tissue comprising: ablock of a porous cellular material of a size to receive a preparedtooth; said block having a groove extending co-extensively thereof toform a dental dam; said groove being adapted to receive the preparedtooth; and an initially flowable material placed within said groove ofsaid block of the porous cellular material, whereby the initiallyflowable material penetrates the pores of the porous cellular materialso that upon setting adheres to the block of the porous cellularmaterial.
 11. A device as defined in claim 10 wherein said groove isU-shaped, and said dental dam having opposed side walls defining saidgroove, said side walls being of sufficient thickness to contain theimpression material when a biting force is applied thereto.
 12. A deviceas defined in claim 10 wherein said groove is V-shaped for use with theanterior teeth.
 13. A device as defined in claim 10 wherein saidcellular material comprises a synthetic foam material.
 14. A device asdefined in claim 10 wherein said cellular material comprises a sponge.